The invention relates to improved methods for reducing color in used lubricating oil.
Reduction of color is an important step in treating used lubricating oils to render them suitable for recycling. Various methods have been described for accomplishing this. For example, PL 2004-364533 describes treatment of spent engine and gear oils with sodium borohydride.
Still, it remains desirable to develop improved, alternate processes for reducing color in used lubricating oil.